The present invention relates to new sialic acid derivatives, in particular, gangliosides or intermediates for producing gangliosides.
In general, glycolipids of mammal cells are the substances which are formed by glycoside linkage between various combinations of various sugars such as glucose, galactose, N-acetylglucosamine, N-acetylgalactosamine, fucose and sialic acid, and a lipid structure called ceramide which in turn is formed through an amide linkage between fatty acid and long-chain aminoalcohol known to as sphingosine. And, these glycolipids belong to a so-called sphingoglycolipid. Among these glycolipids, those which have sialic acid are specifically called gangliosides.
Generally, such compounds locally exist in the outer molecular layer of the bi-layer structure of cell membrane. The current study has proved that these compounds play important roles in cells, such as identification of cells, reception and response to information, receptor function, differentiation, and proliferation, malignant alteration and behavior of cells, and so forth.
It is, however, extremely difficult to isolate oligosaccharides containing sialic acid from a living body. Therefore, fine synthesis of those oligosaccharides is indispensable for clarification of correlation between the accurate biological information and molecular structures of the saccharides.